Method of and apparatus for stereoscopic photography



May 5, 1925.

G. LANE ET AL METHOD OF AND APPARATUS FOR STEREOSCOPIG PHOTOGRAPHY 2 Sheets-Sheet l Filed A a-q 1.92s

(ieo'nge Lane, 2

May 5, 1925.

G. LANE ET AL METHOD OF Ali!) APPARATUS FOR STERBOSCOPIC PHOTOGRAPHY 2 Sheets-Sheet 2 Filed 41 2-. 1923 Invenivra George Lane,

Jbhn lZPafi/ erao mam/M WAQM Ways.

taken, objects relatively far .do not showr up in stereoscopic relief as Patented May 5, 1925. v UNITED STATES PATENT OFFICE.

GEORGE LANE JOHN E. PATTERSON, OI POUGHKEEPSIB, NEW YORK.

METHOD OF AND APPARATUS FOR PHOTOGRAPHY.

Application filed August 11, 1923. sen-1 Io. 850,886.

To all whom it may concern:

Be it known that we, GEORGE LANE and JOHN E. PA'I'IERSON, citizens of the United States, and residents of Poughkeepsie, in the county of Dutchess' and State of New .York, have invented certain new and useful Improvements in Methods of and Apparatus for Stereoscopic Photography, of which the following is a specification.

Our present invention concerns an ad justment of a camera used for the taking of stereoscopic pairs of pictures, and has particularly in mind the elimination of undue eye strain which the viewer experiences when looking at stereoscopic pairs of pictures especially when taken from points separated greater than the distances of separation between the human eyes.

When directly viewing objects, the human eyes focus upon a point in the object, and in so doing the relative angles of the two lines of vision vary with the distance separating the eye andthe object. When the eyes are focusing upon a point far away, the angle of convergence is practicall nil, whereas when viewing an object within a few inches or a' foot from the eyes, the angles of convergence are much larger and appreciable.

In photographing objects in a stereoscopic camera adapted to produce a film for use in moving picture machines, we have found that with the ordinary separation of points from which the stereoscopic pairs are from the camera well, as those objects close at hand. This is due to the factthat the axes-of convergence for the distant objects is less than the axes of convergence in the closer objects; We have found that if the distance of separation of the points from which stereoscopic pairs of pictures is taken is increased, the stereoscopic relief f distant objects is materially ilnproved,an those of closer objects likewise. If, however, in projectin the picture on a screen, the observer ocuses his eyes upon a distant principal object, such as avhorse, and this horse is rapidly moving toward the foreground, it will be ap arent that the axes ofconvergenceof the o rvers eyes are increased as the princi a1 object' in the picture appears to a Vance. There comes a point in the advance of the principal object at which the eyes of the observer, being less separated than the points of separation from which the stereoscopic interest in the rilght and left pictures,

,eye strain is experienced. This condition exists with reference to any object in the picture which appears at a point closer than ten or twelve feet from the observer, but no eye strain is experienced unless the observer attempts to focus his eyes directly upon these objects. This he ordinarily does not. do, inasmuch as the eyes are focused upon the principal object in the picture, and see all others indirectl This invention, their, contemplates a meth ed and means for eliminating the eye strain due to unnatural convergence of axes producedw in the eyes of the observer when stereoscopic pairs 'of'pictures are viewed, and even to reduce the muscular action below that required in normal vision of nature.

Stereoscopic. pairs of pictures, if projected upon the same area of a sensitive surface, would produce two pictures out of register. If the-distance of separation of the points from which the pictures are taken is approximately that of the human eye, and means are used for transmitting the right and left hand pictures to the respective eyes of the observer, the eyes of the observer can take care of this picture without strain. On the other hand, where the distance of separation of the points from which the stereoscopic pairs 0 pictures are taken is increased, as has been shown to be desirable, this out of register circumstance increases proportion ately, wpecially for objects close to the camera. By side-shifting one of the projected pictures, of course any. desired object can be brought into register, and we have found that by properly adjusting the relative lateral position of the principal object of eye strain is practica y eliminated.

We accomplish this by so photographing the pairs of pictures that such object occupics the desired lateral relative location in the-right and left hand negatives, the whole field. of one picture being laterally shifted as required. The amount of required ad-. justment depending upon the distance of the object, as does also the focal settin of the Y may be accomplished,but obviously various other means will occur'to-those skilled in, the art, which must of necessity difl'er from those shown, because of the various designs of tak-. ing cameras, and to which it is advisable that this invention be applied.

In these drawings 2- Figures 1 and 2 are front views of a device embodying our invention, showingmirrors in two positions.

Fig. 3 is. a side elevation.

Figs. 4 and 5 show details of the adjustment mechanism.

Fig. 6 isa plan view.

Fig. 7 is a side elevation.

Referring now with particularity to the form illu trated, we have shown a camera box at 1 havi the usual crank 2 for reelin and exposing Im. A trick shaft 3 to whic is attached a gear 4, meshes with a gear 5, which in turn is connected to the driven gear Wheel 6. The photographic lens of p the camera is illustrated at 7. Verticalmirrors 8 and 9,. preferably the first surface type,

are placed one above the other and mounted upon rods 10 and 11 respectively. These rods are vertically 'reciprocable in bearings 12 and 13. A cross bar 14 connecting the rods 10 and 11 is secured to a pitman 15 which is in turn attached to a crank arm 16 with a counterweight 17. The arm 16 and associated mechanism, is mounted for rotation upon a shaft 18 which carries the gear wheel 6. Thus one-half rotation of the wheel 6 will cau e an extreme vertical movement of the mirrors 8 and 9. The mirror 9 is adapted to occupy a position ,directly in front of, but at substantially 45 to the axis of lens 7, when the crank arm"16 occupies its uppermost vertical position. Likewise the mirror 8 occupies a position in front of, but 45 to the axis of the lens when the crank arm 16 occupies its extreme downward position. Additional mirrors 19 and 19', substantially parallel to the surface of mirrors 8 and 9, are provided to doubly reflect the image of the subject into the lens 7. i 3

within a screw threaded barrel mechanism, or held. frictionally within, a casing, and adapted tobe moved in and out to focus the object uporr the sensitive surface. These instrumentalities are'not illustrated because they are well known, and no invention resides in the use of these parts. An arm 20 connected to and surrounding the. lens 7, may be moved laterally of the camera through a slot 21, to effect the focus of the lens. Movement of the lever 20 in'either direction in the slot will'obviously cause a artial rotation of the lens barrel and thereore, cause the same to approach or recede from the sensitive surface.

Secured to the lever 20 is an arm 22 from whichdepends' a wedge-shaped bar 23. The

having retaining lug camera. Thus for a right-hand he lens 7 is of the usual type, located.

bar 23 is pivotally secured to the end of the arm 22, as by, means of pin 24. V

The mirror 19' is held within a frame 25 26 thereon passing around and engaging the front of the mirror to hold the same in its proper position. To

the frame 25 is secured a member 27 having outwardly extending are attached in a pivota manner, the arms 29 of a similar part 30. This element 30 is bolted" to an upright-31 secured to theframe arms 28 to which of the camera. It willthus be seen that the right 31 and having one portion substantially parallel with the HP-Stfllldlllg .part

33. Theselast two parts are perforated to receive a bolt shank 35 having and adapted to receive a nut 3 on the op- .posite side of the part 33. A spiral spring 38 causes tension to be applied between the parts 33 and 34. The wedge-shaped arm '23 passes between the head 36 of the bolt and the part 34.

ating the usual diaphrain (not shown) be provided to project outwardly a cient distance to allow the same to befeeding of the film past the lens 7, and also rotation of the ar wheel 6. Movement of this latter mem er'causes a reciprocalmotion of the rods 10 and 11 to which mirrors 8. and 9 are connected, thereby-alternately presenting these members to the lens of the P light strikin mirror 19 1S reflected to the mirror 9 an thence into the lens. Further movement of the gear' fi causes the mirror 8 to move fromin front of the lens, thus presenting mirror 9 thereto, and a left-hand picture is then formed as thelight'strikes mirror 19' and is reflected into the mirror 8 and thence into the lens 7 It will be apparent that movement of the mirrors 8 and 9, being in the plane of their surfaces, the exact location is immaterial during the exa head 36 An arm 39, encircling the lens 7 and oper- Rotation of the crank 2 causes the ordinary I I v posure, provided the respectively and alternately cover the fie (1. Movement in their plane duringexposure, has no undesirable efiect. If the m1rrors8and 9 so move dur- As has been described above, it is desir- I able to laterally shift one of the pictures on the-film as the principal object advances-or recedes from the camera, so as to has said ob ect in practically the same laterafposition in both the right and left hand negatives. The shifting of mirror 19 does not alter perceptibly the distance of separation from which the stereoscopic pictures are taken, but moves the view on the negative. Consequently when a positive is projected, a similar movement is carried to the screen. If the principal object is located in the-same spot on the screen as seen by each eye of an observer, regardless of whether it 'is near the camera or far away, it is evident that the angle of convergence of ones eyes need not change in following it. Therefore, muscular effort is reduced. We get the stereoscopic effect just the same because that illusion does not seem to be due to convergence of the eyes at all, but rather to the composite effect of the two different views. This may, obviously, be accomplished b pivoting either of the mirrors 19 or 19'. t

will be apparent that movement of either of.

these mirrors about a vertical axis would have the effect of changing the relative position of the image taken through the lens upon the sensitive surface of the film. This movement need be very minute in order to produce this result. I

It becomes necessary in cameras of this type to adjust the lens for a new focal length where the principal object of a picture advances closer to, or recedes from the camera. We have, therefore, combined the means for adjusting the focus of the lens and the means for causing pivotal movement of one of the mirrors if both operations are desired to be performed at the same time.

. It will be obvious from the drawings that when it becomes necessary to focus the lens by movement of the lever 20 from a position other than that occupied by the lever when at its extreme left position movement toward the right of this lever will cause the arm 22 to be raised. This action causes the wedge-shaped arm 23 to also be raised, thus producing horizontal movement of the bolt 35 against the action of spring 38. As the other end of the bolt moves horizontally it carries with it the up-standing arm 33 which is connected to the frame 25 carrying the mirror 19' and thereby causing rotation of the mirror about its vertical pivot. The degree of movement of the mirror will be determined by practice and can be controlled by varying the leverage on the wedge-shapedmember 23. By this means the out of register circumstance may be entirely or partially corrected, as desired.

What we claim 1s:--

1. An apparatus of the type described including a casing adapted to contain a light sensitive surface, a lens, means to expose the sensitive surface to images of an object viewed from a convergent angle, and means to adjust the position of the images on the sensitive surface, said position adjusting means including a pivoted mirror and means to cause rotation of said mirror about a vertical pivot, said last named means including an arm connected with a focus adjuster attached to the lens.

2. An apparatus of thetype described including a casing adapted to contain a light sensitive surface, a lens, means to expose the sensitive surface to images of an object viewed from a convergent angle, and means .to adjust the position of the images on the sensitive surface, said position adjusting.

means including a pivoted mirror an means to cause rotation of said mirror about a vertical pivot, said last named means including a wedge-shaped arm engaging a member attached to said mirror w ereby movement .of the wedge-shaped arm in'a vertical direction causes horizontal .movement of the member attached to the mirror and .a rotative movement of the mirror.

3. A method oflateral registration in the photographing of stereoscopic pictures which includes the steps of exposing the sen-. sitive surfaces to the images of an object as viewed from spaced apart points, and shifting the focal setting of the lens and shifting the htbeams from one view of the object on' t e sensitive. surface automaticallyin'harmony with the focal setting of the ii fin apparatus of the type described, including a casing adapted to contain a single width light sensitive film strip, a lens, means to focus said lens, means to expose the sensitive-mfa'ce .toimages of an object viewed from a convergent angle, means to adjust the position of t e images on the sensitivesurface, and a mechanical connection between said positioning means and said focusing means. r

In testimony whereof,,we'aflix our signatures.

' GEORGE LANE.

. JOHN E. PATTERSON. 

